Libya's interior minister on Wednesday said U.S. Ambassador Chris Stevens was the State Department officer reported killed Tuesday when armed Islamist militants overran the U.S. consulate in Libya’s second largest city.

Libya's interior minister said Wednesday that the U.S. Ambassador to Libya, Christopher Stevens, was killed when armed Islamist militants overran the U.S. consulate in Libya’s second largest city, in a day of rage that also struck the U.S. Embassy in Cairo, where demonstrators hauled down the American flag, tore it to pieces and burned it.

Secretary of State Hillary Clinton confirmed Stevens' death and said that three other Americans had died, including another diplomat, Sean Smith. The names of the other dead were withheld, pending notification of relatives, Clinton said.

"Our hearts go out to all their families and colleagues," Clinton said in a statement.

At the Pentagon, Defense officials said a Fleet Anti-terrorism Security Team of about 50 Marines was on it's way to Benghazi, though there was no estimate on when they would arrive.

The official said there was no U.S. Marine security detail at the consulate because consulates don't get U.S. Marine security.

"That's usually reserved for embassies," the official, who spoke on condition of anonymity said.

Another Defense official, also speaking on condition of anonymity, said the U.S. embassy in Tripoli has a security team of 18 Marines.

Speaking at the State Department, Clinton said that U.S. and Libyan security personnel battled the attackers together, and that the Obama administration now is working with the Libyan government to identify and track down the assailants.

The United States "will not rest until those responsible for these attacks are found and brought to justice," she said.

The administration, she said, will continue supporting the Libyan government as it struggles to surmount serious insecurity in the aftermath of the civil war that overthrew Gadhafi.

"This was an attack by a small and savage group, not the people or government of Libya," she said.

She praised Stevens as a dedicated diplomat who she first appointed as U.S. envoy to the opposition groups that fought Gadhafi and then as the U.S. ambassador to the new government.

Stevens, she said, "risked his life to stop a tyrant and then risked his life" working to rebuild Libya.

Clinton later joined Obama at the White House as the president condemned the "shocking and outrageous attack" and praised Stevens and other dead U.S. officials as "extraordinary Americans."

Speaking in the Rose Garden, Obama said that the Libyan government was working with the United States to boost security for U.S. diplomatic personnel in the country and track down the assailants, and that security was being increased at U.S. missions around the world.

Obama criticized the film that prompted the protest, but he said that nothing justified the consulate assault.

"Since our founding, the United States has been a nation that respects all faiths. We reject all efforts to denigrate the religious beliefs of others," he said. "But there is absolutely no justification for this type of senseless violence. None. The world must stand together to unequivocally reject these brutal acts."

Like Clinton, Obama said that the attack would not undermine U.S. support for the Libyan government.

"Libyan security personnel fought back against the attackers alongside Americans. Libyans helped some of our diplomats find safety, and they carried Ambassador Stevens' body to the hospital, where we tragically learned he had died," he said.

Libyan authorities said Stevens, 52, died of smoke inhalation, but the details of the attack were hazy.

Stevens' death marked the loss of one the State Department's best Libyan experts and threatened to mar relations between the United States and Libya's nascent government.

Stevens had focused most of his diplomatic career on the Middle East, spending time in Cairo, Riyadh and Jersusalem. He first arrived in Libya in 2007 and returned in the spring of 2011 in the early days of the uprising against then Libyan leader Moammar Gadhafi.

At that time, he met with officials who would become key members of the National Transitional Council and eventually Libya's first democratically elected government, which was seated last month. He assumed the role of ambassador in May of this year.

An Arabic speaker, Stevens told McClatchy during a spring 2011 interview that he particularly loved Libya, even as he served as a diplomat there during Gadhafi's time. Other diplomats remembered him as deeply engaged in all the Middle East, however.

"He knew our issues really well," said Abi Khair, a diplomat at the Jordanian embassy in Washington who had met Stevens in the days after Gadhafi's fall when Khair served with the United Nations. "He was passionate about them."

Stevens' cables on Libya, which were among the trove released by WikiLeaks, offered colorful insights on Gadhafi and al Qaida's push to expand in Libya.

In an August 2008 cable he wrote to prepare then Secretary of State Condoleezza Rice for a visit with Gadhafi he described the Libyan leader as “a self-styled intellectual and philosopher, he has been eagerly anticipating for several years the opportunity to share with you his views on global affairs.” During the fall of his regime, Libyans recovered a photo album Gadhafi had made containing photos of Rice.

When asked by McClatchy about the blunt nature of his cables, Stevens simply smiled and shrugged.

By the time Stevens returned to Libya he was perhaps the most celebrated ambassador in the Middle East, well known and respected among Libya's 6 million people. Throughout Twitter and Facebook, popular Libyan sites, first created during the uprisings, mourned his loss and said that his death was no way to defend Islam.

"I'm shocked," one Arab diplomat who knew Stevens said, asking that he not be identified by name because he was not authorized to discuss the issue. "Immediately after the collapse of the (Gadhafi) regime, there were U.S. flags everywhere and thank yous to Obama. But in one incident, things have turned worse than before."

The protests at the U.S. consulate in the eastern city of Benghazi, the birthplace of the Libyan revolution, were spurred by a movie clip that mocked the Prophet Mohammed, drawing the ire of Islamists in both Egypt and Libya.

In her statement late Tuesday, Clinton said she had asked Libya’s government to provide additional protection to Americans in Libya and said she would ask other governments to beef up their security precautions.

The storming of U.S. diplomatic compounds in Benghazi and Cairo, where no one was injured, took place on the 11th anniversary of the Sept. 11 terrorist attacks but appeared to be sparked by outrage over the release of a movie trailer that conservative Muslims in both countries said denigrated Islam and its holiest figure, Mohammed. Clinton acknowledged that as the likely cause in her statement.

“Some have sought to justify this vicious behavior as a response to inflammatory material posted on the Internet. The United States deplores any intentional effort to denigrate the religious beliefs of others,” she said. “But let me be clear: There is never any justification for violent acts of this kind.”

Backers of the movie, who included Terry Jones, the Florida pastor whose burning of Qurans last year led to days of rioting in Afghanistan, were unapologetic about the role their film may have had in triggering the violence.

“The fact that angry protesters climbed the wall at the U.S. embassy in Cairo today, ripped down the American flag and tore it apart further indicates the lack of respect that Islam has for any other religion, any other flag, any freedom of speech, freedom of expression and freedom of religion,” Jones said in a statement released before the death in Benghazi was confirmed. “It further illustrates that they have no tolerance for anything outside of Mohammad.”

Even without the provocation provided by the film, the violence fit a pattern of growing fundamentalist ferment that has touched many of the countries where governments have fallen in the past 18 months.

That trend has been especially pronounced in Libya, where in recent weeks conservative Islamists have leveled mosques and cemeteries associated with the moderate Sufi strain of Islam, and car bombs have become increasingly frequent in Tripoli, the capital, and Benghazi. In what can only be considered ironic, the United States, which had backed the NATO bombing campaign that helped rebels defeat the government of Moammar Gadhafi last year, has warned its citizens to defer all but essential travel to Libya because of the country’s deteriorating security situation.

The protest in Cairo also came at an ironic moment: The U.S. Embassy has been urging companies to invest in Egypt, saying it is now stable.

Egyptian police did little to discourage thousands of protesters who descended on the U.S. Embassy and they stood by as the protesters first sprayed paint on the 12-foot wall that surrounds the compound, then stormed over the wall, where hundreds converged on the flagpole, pulling down the standard, shredding it and burning the remnants.

As the flag was torn and then set on fire, a man climbed a ladder alongside the flagpole and replaced the flag with one that read, "There is no God but Allah and Mohammed is his messenger.”

Among the chants yelled toward the embassy was, “Take a picture, Obama, we are all Osama,” a reference to Osama bin Laden, who planned and financed the 9/11 attacks and whom U.S. commandoes killed on May 2, 2011.

"Say it, don’t fear: Their ambassador must leave," was another.

Organizers of the embassy protest said they’d begun planning the event last week when a controversial Egyptian Christian activist who lives in the United States, Morris Sadek, released a trailer for a movie called “Muhammad,” which repeatedly mocks the prophet and the religion. The 14-minute clip, which Sadek first posted on his Facebook page Sept 5, attacked basic tenets of Islam and suggested that the religion had spread only because the prophet told those he encountered to “pay extortion or die” if they didn’t convert.

Christians make up roughly 10 percent of Egypt’s population, and officials from Egypt’s Coptic churches have condemned the film.

The film controversy came as Jones announced Tuesday that he planned to put the prophet on trial in what he called International Judge Muhammad Day.

In a video announcing the “trial,” Jones, wearing a black shirt with the word “Infidel” printed on it in Arabic, said that he planned to charge the prophet “with being a false prophet, thus leading 1.6 billion people astray.”

The embassy had tried to pre-empt the attack, issuing a statement hours earlier that condemned “the actions by those who abuse the universal right of free speech to hurt the religious beliefs of others.” Embassy officials also called Nader Bakkar, a spokesman for the conservative Islamist Nour party, in which they apologized for the film and Jones’ call, but Bakkar said he was unwilling to call off the protest, and embassy employees were sent home early.

“The American people must know we do not accept any kind of insult of the prophet, peace be upon him,” Bakkar said, adding that he nevertheless opposed pulling down the American flag.

In Benghazi, which had been the seat of the anti-Gadhafi rebel forces, armed Islamists apparently led the charge on the U.S. consulate. Witnesses said that they heard loud explosions nearby and that armed men had surrounded the area around the consulate, blocking the road and making it impossible for reporters to film the scene. The gunmen then set the building on fire.

One man, who asked not to be identified for security reasons, said the attackers were conservative Islamists, who generally do not shave. “I was stopped by a guy whose beard extended to his knees," the man said, in an exaggeration. "And he told me very proudly not to pass because we have burned the American consulate."

Looters carried off office furniture and appliances from the consulate compound and passers-by entered the compound to take photos with their cell phones.

The Reuters news agency quoted a spokesman for Libya’s Supreme Security Committee, Abdel-Monem al Hurr, as saying that Libyan security forces at the scene had been overwhelmed by the attackers.

Islam forbids any depiction of Mohammed because he’s seen as someone whose greatness can’t be replicated. In documentaries about his life, he’s often portrayed as a ray of light. That someone would mock the prophet is considered blasphemous.

Sharif Abdel Meniem, 29, who helped organize the Cairo protest, said he planned the demonstrations “because the Americans did not take a real stand against” Jones’ call.

“The prophet does not have a hand in the 9/11 attacks,” he said as chanters yelled, “The prophet’s army has arrived.”

That the protest fell on Sept. 11 wasn’t lost on those participating.

“This anniversary provokes the United States,” said Islam Mustafa, 23, a student. “But (Americans) are the ones provoking us.”